The Bone—Vasculature Axis: Calcium Supplementation and the Role of Vitamin K (Wasilewski et al.)
A review paper published recently in Frontiers in Cardiovascular Medicine provides an insight into therapeutic strategies with vitamin K2 treatment to prevent or hold progression of vascular calcification as a consequence of excessive calcium supplementation.
Throughout life calcium is important for optimal bone health. Various calcium supplements are the most commonly used non-prescription drugs to treat age-related bone loss. However, post-menopausal osteoporotic women and patients suffering from chronic kidney disease (CKD) are often prone to impaired calcium metabolism that results in the calcium paradox. This term describes the paradoxical correlation between lower bone calcium content with parallel increased arterial calcification. The discovery of extra-hepatic vitamin K-dependent proteins (VKDP), including Osteocalcin (OC), Matrix Gla Protein (MGP), and Gla Rich Protein (GRP) has shed some light on proper calcium intake. VKDP are a group of proteins that require carboxylation of specific protein-bound glutamate-residues, allowing them to bind with high affinity to calcium. The functions of non-hepatic VKDP include prevention of vascular calcification and importantly also promotion of bone metabolism. Comparison of data from various trials showed that MK-7 (MenaQ7), a long-chain menaquinone, was found to have more beneficial effect on bone and facilitates bone mineralization, including cortical bone structure as compared to MK-4. Inactive MGP (dp-ucMGP) has been correlated with severity of CKD and is positively associated with amount of vascular calcification. MK-7 (MenaQ7) supplementation in patients with CKD3-5 significantly reduced circulating levels of dp-ucMGP.
The authors emphasize that, “Clinical studies demonstrate that increased intake of vitamin K could be a promising complementary nutrient in supporting both bone health and protecting vascular calcification. Thereby it can increase safety of current treatments of osteoporosis and provide an escape from the calcium paradox.”
“Vitamin K2 supplementation in combination with calcium and vitamin D3 is very beneficial in post/peri-menopausal patients, since it protects from increased risk for vascular calcification and allows for more safe treatment of osteoporosis,” explains Dr. Katarzyna Maresz, president of the International Science and Health Foundation. “Vitamin K2 is also an important factor in bone and vasculature in CKD patients who are frequently vitamin K-deficient and prone to coronary calcification.”
References:
Wasilewski GB, Vervloet MG and Schurgers LJ (2019) The Bone—Vasculature Axis: Calcium Supplementation and the Role of Vitamin K. Front. Cardiovasc. Med. 6:6. doi: 10.3389/fcvm.2019.00006